GENETIC AND OTHER FACTORS IN SCHIZOPHRENIC, MANIC-DEPRESSIVE, AND SCHIZO-AFFECTIVE PSYCHOSES

Abstract

The major psychoses were investigated for genetic and environmental etiological factors for more than 2 centuries. Recent emphasis was placed on a genetic (diathesis) environmental stress model. For schizophrenia, manic-depressive and schizo-affective psychoses, research evidence from psychobiological studies, family, pedigree, twin and adoptee studies indicates, and new psychopharmacological research that for these 3 major psychoses a strong necessary but not sufficient basis for genetic causation exists. A resulting hypothesis suggests that 2 separate gene pools of polygenic nature relate to the development of schizophrenia and manic-depressive illness and that schizo-affective illness may result from genetic transmission from each of these separate gene pools. The hypothetical model for each psychosis proposes that polygenetic inheritance affects different CNS neuroanatomical sites in the human which are in homeostasis as to catecholamine neurotransmitter regulation of the psyche. With sufficient environmental stress, an imbalance occurs in the neural integrative systems which produces phenotypically the 3 separate psychotic behavioral syndromes of schizophrenia, manic-depressive psychosis and schizo-affective psychosis.